The tot was in the back of his family car driving through Los Angeles when his mum, Crystal's daughter Lindsay, pulled up alongside a bus advertising his new series, in which he plays Frozen star Josh Gad's TV sidekick.

The funnyman says, "She (Lindsay) hears her son go, 'Grandpa, hi grandpa... Grandpa has a bus, grandpa has a bus...

"So now he comes over and he wants to see my bus, so I'm trying to tell him, 'I don't have a bus', and he gets mad..."

Crystal jokes, "So I bought a bus!"